A Bronx girl was killed by a tractor-trailer after leaving her job at Dylan’s Candy Bar on the Upper East Side.Byron Smith

NTSB investigators will be looking at the following four scenarios in the crash of Flight 587:

* TERRORISM: Although there are no outward signs of a terrorist attack – no indications from the cockpit or tower, no signals at U.S. intelligence agencies and no evidence from the FBI – probers will be combing the passenger manifest and wreckage for any clues indicating it was a hostile action.

* MECHANICAL FAILURE: One of Flight 587’s CF6-8 engines had more than 9,000 hours of use. After 10,000 hours of activity, an engine requires a so-called “major maintenance.” or overhaul. That model engine has had a history of problems.

* INGESTION OF BIRDS: A bird sucked into the engine of a plane can disrupt its cooling mechanism, which then may lead to overheating or an explosion. It’s been a longtime problem at JFK.

* STRUCTURAL INTEGRITY OF THE AIRCRAFT: Because both engines fell off the plane, investigators will check to see how the engines were braced to the wings, X-raying the relatively young fuselage for stress cracks.